BPy Funtcion long to short?
You can put the items in an array and then run a loop:

def execute(self, context):
    parts = ['Body_00_Default', 'Body_01_Idle', 'Body_02_Attack', 'Body_03_Block', \
        'Leg_00_Default', 'Leg_01_Walk', 'Leg_02_Run']

    for part in parts:
        bpy.context.object.animation_data.action = bpy.data.actions[part]
        bpy.ops.anim.keyframe_clear_v3d()

    return {'FINISHED'}


or if you really want to clear ALL the actions, you could try

for act in bpy.data.actions:
    bpy.context.object.animation_data.action = act
    bpy.ops.anim.keyframe_clear_v3d()